Global journal 44

www.iiece.org GJESR RESEARCH PAPER VOL. 1 [ISSUE 10] NOVEMBER, 2014

ISSN:- 2349–283X

COMPARITIVE STUDY OF THE PROPERTIES OF FLY ASH CLAY BRICKS AND CLAY BRICKS 1Ramji

Porwal Department of Civil Engineering, Madan Mohan Malviya University of Technology, Gorakhpur, India Email: ramporwal123@gmail.com Abstract: Brick is one of the most widely used construction materials throughout the world since ancient time. Fly ash clay bricks are one of the best alternatives to the conventional burnt clay bricks. This dissertation gives the results of an experimental investigation in which the compressive strength, water absorption, density and durability of Fly ash-clay bricks are investigated by using varying quantities of fly ash with partial replacement of clay. The properties of Fly ash clay bricks are compared with those of the ordinary burnt clay bricks. The results indicate that these bricks are lighter in weight, durable in aggressive environments and have sufficient strength for their use in building construction.

Keywords: Fly ash; Brick; Clay; Sand; Compressive Strength.

1. GENERAL- .Fly Ash from the NTPC TANDA

In India, construction industry shares a part about

(U.P.) plant produces 6-800 tons of fly ash per day,

9 % of the Gross Domestic Product (GDP), and

over 20 MT a year, in the form of dry Bottom Ash.

annual growth of about 10%. Clay bricks are the

Gorakhpur is situated only 111 km away from the

main building material for the construction

NTPC Tanda, Ambedkar Nagar (U.P.). Energy

industry and housing. In developing countries in

requirements for the countries for electricity get

the world, India is one of the largest with the

energy from coal. Thermal power stations use

economic growth rate averaging 9% for the last 5

pulverized coal as fuel generates large quantities

years plan so that this growth rate will also effect

of fly ash as by-product. The disposal of the

on the construction work and GDP. The brick

thermal waste is called fly ash. Fly ash is a

technology in India varies from region to region

powdery substance collected by the electrostatic

and depends generally on scale of production, soil

precipitators in the thermal power plants. There

and fuel available, demand, market conditions and

are about 125 thermal power plants in India,

also on the enforcement of law for shifting from

which form the major source of fly ash in the

one

technology

to

the

other

country (Kumar and Singh, 2006).

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GJESR RESEARCH PAPER VOL. 1 [ISSUE 10] NOVEMBER, 2014

ISSN:- 2349–283X

Share in world brick production

11% 23%

India China Bangladesh

8%

Pakistan 4%

other Countries

54%

Fig 1 Share in world brick production The GOI (Government of India) on 14th September

elongated shape. Their specific surface is infinitely

1999, published in the Gazette under S.O. 763 (E),

greater than that of rougher round or angular

Directions under the Environment (Protection)

particles. Clay is one of the most mineral materials

Rules, notifying the “Use of fly ash, bottom ash

on all over the earth for bricks.

or pond ash in the manufacture of bricks and other construction activities.” (Annex 14). It requires brick-makers within a radius of 50 KM from thermal coal or lignite-based power plants to use at least 25% by weight of ash to

Clays occur in three principal forms, all of which have similar chemical compositions but different physical characteristics.

1.

Surface Clays- Surface clays may be the up thrusts of older deposits or of more recent

be mixed with soil for brick-making.

sedimentary formations. As the name implies,

2. RAW MATERIALS- The raw materials which

they are found near the surface of the earth.

are used for the making of bricks are as follows2.

Shale- Shale is clays that have been subjected

(i) Clay- Clay is a fine grained soil. It is a cohesive

to high pressures until they have nearly

soil. The particle size is less than 0.002 mm. It is

hardened into slate.

usually dark grey or black in colour. It is

3.

Fire Clays- Fire clays are usually mined at

conspicuous odour. They differ from other grains

deeper levels than other clays and have

in their chemical composition and physical

refractory qualities.

properties. In chemical terms they are hydrated

(ii) Fly Ash- A fine glass powder recovered from

alumina-silicates formed by the leaching process

the gases of burning coal during the production of

acting on the primary minerals in rock. Physically

electricity is fly ash. These micron sized earth

speaking, clay very often assumes a platy

elements consist primarily of silica, alumina and

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GJESR RESEARCH PAPER VOL. 1 [ISSUE 10] NOVEMBER, 2014

ISSN:- 2349–283X

iron. The combustion of powdered coal in thermal

These micron sized earth elements consist

power plants produces fly ash. The high

primarily of silica, alumina and iron. The

temperature of burning coal turns the clay

combustion of powdered coal in thermal power

minerals present in the coal powder into fused

plants produces fly ash. The high temperature of

fine particles mainly comprising of aluminum

burning coal turns the clay minerals present in the

silicate. Fly ash produced thus possesses both

coal powder into fused fine particles mainly

ceramic and pozolanic properties. A fine glass

comprising of aluminum silicate. Fly ash produced

powder recovered from the gases of burning coal

thus possesses both ceramic and pozolanic

during the production of electricity is fly ash.

properties.

Table 1: Physical Properties of Fly Ash Sl. No.

Constituent/Property

Value

1

Colour

Grey

2

Percent passing 75µ sieve

76%

3

Size of particle

0.002-0.30mm

4

Maximum Dry Density (MDD)

1.183g/cc

5

Optimum Moisture Content

22%

6

Specific Gravity

2.02 at 270C

8

Plastic Limit

Non-plastic

9

Classification

Class C and Class F

3. METHODOLOGY OF MAKING BRICKS-

5) Drying of Bricks.

Clay fly ash brick manufacturing is most suitable for transition with minimum changes from existing practices and manual molding of bricks, which is most common. CBRI technology is well tried and tested. These can also have semimechanized operations, but manual operations are most effective cost. There are many processes which are used for the manufacturing of Bricks.

The major steps in preparation of bricks by Chimney Kilns process are as follows:1) Collection of Different clay and Fly ash.

2) Mixing and preparation of clay-fly ash mix.

6) Filling of Kiln.

7) Burning of kiln.

8) Inspection and sorting of Bricks according to grades.

Fly

Ash-Clay

Brick:

(As

per

CBRI)

Brick

Composition: Fly Ash - 30% and Clay- 70%.We have taken five samples of clay and fly ash i.e.

1) Clay- 75% and Fly Ash -25% 2) Clay- 70% and Fly Ash -30% 3) Clay- 65% and Fly Ash -35% 4) Clay- 60% and Fly Ash -40% 5) Clay- 55% and Fly Ash -45%

3) Preparation of Bricks through moulds.

4) Moulding Procedure

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GJESR RESEARCH PAPER VOL. 1 [ISSUE 10] NOVEMBER, 2014

Fly Ash

ISSN:- 2349–283X

Clay

Proportion of Fly Ash & Clay

Dry Mixing & Pulverization

Water

Wet Mixing

Moulding of Bricks

Sun Drying

Setting the Bricks in kiln for firing for 14 days da Cooling for 3-4 days

Testing the Bricks for WA & CS

Analysis of Results Fig 5.8 Flow chart showing methodology of bricks

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GJESR RESEARCH PAPER VOL. 1 [ISSUE 10] NOVEMBER, 2014 the

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4. EXPERIMENTAL SET UP & PROCEDURE-

from

bricks

stack.

Any

blister,

small

Tests are conducted for the acceptance of bricks

projections or loose particles of clay that adhered

for building construction. We have to be very sure

to each brick are removed.

about strength and worthiness of basic building unit i.e. Bricks. Following tests are performed to check the quality of bricks4.1. DIMENSION AND TOLERANCE TESTFor the bricks dimensions measurement, the procedures

is

based

on

Clause

5.2.1,

IS

12894:2002. The required apparatus in this test is measuring tape. The number of specimens for the test shall be selected according to IS 5454:1976. In this test, a total of 10 bricks are selected randomly Table 2: Size of bricks SIZE OF BRICK

LENGTH (mm) 230

WIDTH

HEIGHT

(mm)

(mm)

120

75

PLAN AREA (mm2) 27600

4.2 WATER ABSORPTION TEST

is absorbed. The total water absorption is defined

The Bricks are weighed dry. Then they are

as the increase in the weight of a material due to

immersed in water for a period of 24 hours.

moisture in air, and procedure is as follows-

Samples are taken out and wiped with cloth. The Water absorption in (%) =

weight of samples in wet condition is determined.

× 100%

The differences in weights indicate that the water Sl. No.

% OF FLY ASH ADDED

1

25

14.785

14.774

14.919

14.457

14.822

14.751

2

30

18.857

17.575

18.329

17.441

17.106

17.861

3

35

16.636

16.961

17.047

16.949

17.366

16.991

4

40

17.909

17.495

17.780

17.523

17.988

17.154

5

45

16.566

17.091

17.047

17.338

17.731

17.739

Sl. No.

WATER ABSORPTION (%) SA-1

SA-2

SA-3

SA-4

SA-5

AVERAGE

WATER ABSORPTION OF CLAY BRICKS (%) SA-1

SA-2

SA-3

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SA-4

SA-5

AVERAGE

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GJESR RESEARCH PAPER VOL. 1 [ISSUE 10] NOVEMBER, 2014

ISSN:- 2349–283X

N1

14.571

12.527

13.812

13.295

12.484

13.337

N2

14.976

14.785

14.042

13.426

14.085

14.262

N3

14.746

15.079

12.305

14.542

13.469

14.028

N4

14.961

14.774

12.416

14.263

13.787

14.032

N5

15.152

13.888

14.944

14.065

14.960

14.601

4.3 COMPRESSIVE STRENGTH TEST

compressive strength the following dimensions

The Test is conducted as per IS-3495, Part-1,

are taking as average dimension. The calculation

1992. The load is applied axially at a uniform rate

for the compressive strength of bricks is as:

of 15 N/mm2. The crushing load is noted as IS an (Indian Standard) code permitting the limits for

Compressive Strength =

the good quality bricks. Calculation of the COMPRESSIVE STRENGTH OF CLAY BRICKS(N/mm2)

Sl. No.

SA-1

SA-2

SA-3

SA-4

SA-5

AVERAGE

N1

9.601

9.782

9.420

9.239

9.420

9.420

N2

9.963

9.601

9.782

9.963

9.963

9.601

N3

10.14

10.32

9.963

9.782

9.420

9.420

N4

9.420

9.601

9.782

9.963

10.50

10.32

N5

9.601

9.239

9.420

9.420

9.420

9.782

Sl. No.

% OF FLY ASH ADDED

COMPRESSIVE STRENGTH OF FLY ASH CLAY BRICKS (N/mm2) SA-1

SA-2

SA-3

SA-4

SA-5

AVERAGE

A

25

6.34

6.15

6.08

6.34

6.88

6.35

B

30

6.70

7.06

6.34

7.24

7.42

6.95

C

35

8.69

8.51

9.23

8.87

9.42

8.94

D

40

5.61

7.24

6.15

6.08

5.43

6.10

E

45

5.97

5.79

5.61

5.97

5.79

5.82

4.4 EFFLORESCENCE TEST

immersed in water for 24h. It is then taken out

In bricks presence of the soluble salts cause

and allowed to dry in shade. The absence of grey

efflorescence on the surface of brick. Brick is

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GJESR RESEARCH PAPER VOL. 1 [ISSUE 10] NOVEMBER, 2014

ISSN:- 2349–283X

or white deposits on its surface indicates absence

observations are made from fly ash clay bricks

of soluble salts.

with different percentage of fly ash and also

Observation is made with naked eyes and

minimize impacts on the environmental by

classified as below.

utilization of Class F fly ash in the manufacturing

 Nil

–

No

patches

or

imperceptible

of bricks .The present research replicate the effect

efflorescence.

of waste product like Fly Ash on compressive

 Slight – 10% of area covered with deposits.

strength of brick and results is obtained. The

 Moderate – 10 to 50% area covered with

results of Fly Ash Clay Bricks and Clay Bricks are

deposit but unaccompanied by flaking of the

as per IS-1077 – 1992 and IS-13757 – 1993

surface.

respectively. From the experimental results

 Heavy – More than 50 per cent area covered

obtained, it can be concluded that

with deposits but unaccompanied by flaking

1) The burnt bricks manufactured with fly ash

of the surface.

appearance when compared to the clay bricks, the

 Serious – Heavy deposits of salt accompanied

percentage of water absorption for bricks is found

by flaking of the surface

to be less than that of conventional bricks but still

5. RESULTS AND CONCLUSION-

within the prescribed maximum limit as per

After all the efforts and learning of local

Indian Standards maximum is 20%. The Clay

technologies and practices and with the help of

burnt bricks, when tested in accordance with the

experimental

procedure

investigation,

the

following

20 18

WATER ABSORPTION ( % )

16 14 12 10 8 6 4 2 0

A

N1

B

N2

C

N3

D

N4

E

N5

FLY ASH CLAY BRICKS

14.751

17.861

16.991

17.154

17.739

CLAY BRICKS

13.337

14.262

14.028

14.032

14.601

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2) The Clay bricks having fly ash as an admixture

conclude that compressive strength of Fly Ash

showed

Clay bricks is good than the clay bricks. We can

the

best

performance,

having

a

compressive strength of near about conventional

use it for future work as a building material.

bricks. In this figure the compressive strength of Fly Ash Clay Bricks is similar to the Clay Bricks against the 35% fly ash added. Hence we can

COMPRESSIVE STRENGTH (N/mm2)

12

10

8

6

4

2

0 A

N1

B

N2

C

N3

D

N4

E

N5

SAMPLE OF BRICKS 3) Finally it can be concluded from the above experiments, the properties of the fly ash clay burnt bricks which are as given belowOptimum % of fly ash addition

35%

Water Absorption (at 35% Fly Ash)

17 %

Compressive Strength (at 35% Fly Ash):

8.94 N/mm2

The properties of clay bricks are as followsWater Absorption

14.6 %

Compressive Strength

10.32N/mm2

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GJESR RESEARCH PAPER VOL. 1 [ISSUE 10] NOVEMBER, 2014

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Hence the bricks may be termed as Class 7.5 as per BIS: 3492 Part 2: 1992 and the Class 10 as IS 13757:1993, the water absorption up to class 12.5 should be less than 20% as per IS 3495 (Part 2): 1992. The bricks prepared confirm to this criterion too Sl.

CLAY BRICKS

FLY ASH CLAY BRICKS

1

Varying colour as per soil

Uniform pleasing colour like cement

2

Uneven shape as hand made

Uniform in shape and smooth in finish

3

Lightly bonded

Dense composition

4

Plastering required

No plastering required

5

Heavier in weight

Lighter in weight

6

Compressive strength is around 10.02N/mm2

Compressive strength is around 8.94 N/mm2

7

More porous

Less porous

No.

CONCLUSIONS-

buildings as well as houses and also no

1) Thermal conductivity Of Fly Ash Bricks is

breakage during transport use.

0.90-1.05

W/m2

ºC

while

thermal

3) Fly ash clay bricks have less porous, absorbs

conductivity Of Normal Clay Bricks is 1.25 –

very little water, whereas burnt clay bricks

1.35 W/m2 ºC so FACB (fly ash clay bricks)

absorbs more water during construction.

absorbs less heat than normal bricks, it keeps

Sprinkling of water before use is enough.

your building cool even in summer, hence

Saves money on water during construction

most suitable for Indian conditions.

and even keeps your building strong during

2) Fly ash bricks are light weight bricks

rainy seasons.

compared to clay bricks. These are 25%

4) Fly ash clay bricks are high quality bricks and

lighter than the clay bricks, so it is suitable for

do not have the cracks on its surface. Surface

multi storey building. Less weight means less

is neat and clean and plaster (Plaster of Paris)

stress on the building, safety assured. These

can be directly applied on these bricks

bricks will reduce the structural load and also

without a backing coat of lime.

reduce the construction cost. Hence these

5) Clay

bricks are suitable for the construction of

can

be

used

as

a

chemical

accelerator/binder for Fly ash clay bricks as fly ash is non-plastic. Fly ash clay bricks are

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GJESR RESEARCH PAPER VOL. 1 [ISSUE 10] NOVEMBER, 2014

ISSN:- 2349–283X

cheaper than ordinary “First class Clay Brick”

[3] Indian Standard, Guidelines For Utilisation

and cost effective in use and environment

and Disposal of Fly Ash, IS: 10153 - 1982,

friendly. Fly ash clay bricks result in

Indian Standards Institution, New Delhi

efflorescence is less or negligible.

[4] O. Kayali, “High performance bricks from fly

6) Clay which is used for manufacturing of clay

ash”, Proceedings of the World of Coal Ash

bricks so need for conservation of natural

Conference, Lexington, Kentucky, 2005.

resources. By consuming 80-82% fly ash, the

[5] Chou Mie-In (2002), “Fired Bricks from Fly

cause of environmental pollution and hazards

Ash”, A Report Published by the Illinois State

due to disposal is minimized.

Geological Survey, a Division of the Illinois, Department of Natural Resources, 615 East

REFERENCES-

Peabody Drive Champaign, IL 61820-6964, USA, 2002

[1] Kumar, V. (2006): “Fly ash: A resource for sustainable

development’,

Proc.

of

[6] Nirvan G. (2008), “It’s Time to Go in for Green

the

Bricks

International Coal Congress & Expo, 191-199.

Strength Materials

of to

Bricks

Made

Clay

Bricks.”,

With

PrachaR

–

Integrated

Communications Consultant, The Hindu, On-

[2] Aashish Kumar Parashar, Rinku Parashar (2012), “Comparative Study on compressive

now”,

line Edition, September 6th, 2008.

[7] ASTM E 1861 (1997) “Standard guide for the

Various

International

use of coal combustion by products in structural fills.” Philadelphina, U.S.A.

Journal of Science and Research Publication, Volume 2, Issue 7, July.

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